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Chronic kidney disease
Definition
Chronic kidney disease is the slow loss of kidney function over time. The main function of the kidneys is to remove wastes and excess water from the body.
Alternative Names
Kidney failure - chronic; Renal failure - chronic; Chronic renal insufficiency; Chronic kidney failure; Chronic renal failure
Causes
Chronic kidney disease (CKD) slowly gets worse over time. In the early stages, there may be no symptoms. The loss of function usually takes months or years to occur. It may be so slow that symptoms do not appear until kidney function is less than one-tenth of normal.
The final stage of chronic kidney disease is called end-stage renal disease (ESRD). At this stage, the kidneys are no longer able to remove enough wastes and excess fluids from the body. The patient needs dialysis or a kidney transplant.
Chronic kidney disease and ESRD affect more than 2 out of every 1,000 people in the United States.
Diabetes and high blood pressure are the two most common causes and account for most cases.
Many other diseases and conditions can damage the kidneys, including:
- Autoimmune disorders (such as systemic lupus erythematosus and scleroderma)
- Birth defects of the kidneys (such as polycystic kidney disease)
- Certain toxic chemicals
- Glomerulonephritis
- Injury or trauma
- Kidney stones and infection
- Problems with the arteries leading to or inside the kidneys
- Some pain medications and other drugs (such as cancer drugs)
- Reflux nephropathy (in which the kidneys are damaged by the backward flow of urine into the kidneys)
- Other kidney diseases
Chronic kidney disease leads to a buildup of fluid and waste products in the body. This condition affects most body systems and functions, including:
- Blood pressure control
- Red blood cell production
- Vitamin D and bone health
Symptoms
The early symptoms of chronic kidney disease are also symptoms of other illnesses. These symptoms may be the only signs of kidney disease until the condition is more advanced.
Symptoms may include:
- Appetite loss
- General ill feeling and fatigue
- Headaches
- Itching (pruritus) and dry skin
- Nausea
- Weight loss without trying to lose weight
Other symptoms that may develop, especially when kidney function has gotten worse, include:
- Abnormally dark or light skin
- Bone pain
- Brain and nervous system symptoms:
- Drowsiness and confusion
- Problems concentrating or thinking
- Numbness in the hands, feet, or other areas
- Muscle twitching or cramps
- Breath odor
- Easy bruising, bleeding, or blood in the stool
- Excessive thirst
- Frequent hiccups
- Low level of sexual interest and impotence
- Menstrual periods stop (amenorrhea)
- Shortness of breath
- Sleep problems, such as insomnia, restless leg syndrome, and obstructive sleep apnea
- Swelling of the feet and hands (edema)
- Vomiting, typically in the morning
Exams and Tests
High blood pressure is almost always present during all stages of chronic kidney disease. A nervous system exam may show signs of nerve damage. The health care provider may hear abnormal heart or lung sounds when listening with a stethoscope.
A urinalysis may show protein or other changes. These changes may appear 6 months to 10 or more years before symptoms appear.
Tests that check how well the kidneys are working include:
- Creatinine clearance
- Creatinine levels
- BUN
Chronic kidney disease changes the results of several other tests. Every patient needs to have the following checked regularly, as often as every 2 - 3 months when kidney disease gets worse:
- Albumin
- Calcium
- Cholesterol
- Complete blood count (CBC)
- Electrolytes
- Magnesium
- Phosphorous
- Potassium
- Sodium
Causes of chronic kidney disease may be seen on:
- Abdominal CT scan
- Abdominal MRI
- Abdominal ultrasound
- Kidney biopsy
- Kidney scan
- Kidney ultrasound
This disease may also change the results of the following tests:
Treatment
Controlling blood pressure will slow further kidney damage.
- Angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) are used most often.
- The goal is to keep blood pressure at or below 130/80 mmHg
Other tips for protecting the kidneys and preventing heart disease and stroke:
- Do not smoke.
- Eat meals that are low in fat and cholesterol.
- Get regular exercise (talk to your doctor or nurse before starting to exercise).
- Take drugs to lower your cholesterol, if needed.
- Keep your blood sugar under control.
- Avoid eating too much salt or potassium.
Always talk to your kidney doctor before taking any over-the-counter medicine, vitamin, or herbal supplement. Make sure all of the doctors you visit know you have chronic kidney disease.
Other treatments may include:
- Special medicines called phosphate binders, to help prevent phosphorous levels from becoming too high
- Treatment for anemia, such as extra iron in the diet, iron pills, iron through a vein (intravenous iron) special shots of a medicine called erythropoietin, and blood transfusions
- Extra calcium and vitamin D (always talk to your doctor before taking)
You may need to make changes in your diet. See: Diet for chronic kidney disease for more details.
- You may need to limit fluids.
- Your health care provider may recommend a low-protein diet.
- You may have to restrict salt, potassium, phosphorous, and other electrolytes.
- It is important to get enough calories when you are losing weight.
Different treatments are available for problems with sleep or restless legs syndrome.
Everyone with chronic kidney disease should be up-to-date on important vaccinations, including:
- H1N1 (swine flu) vaccine
- Hepatitis A vaccine
- Hepatitis B vaccine
- Influenza vaccine
- Pneumococcal polysaccharide vaccine (PPV)
When the loss of kidney function becomes more severe, you will need to prepare for dialysis or a kidney transplant.
- When you start dialysis depends on different factors, including your lab test results, severity of symptoms, and readiness.
- You should begin to prepare for dialysis before you need it. Learn about dialysis and the types of dialysis therapies, and how a dialysis access is placed.
- Even people who are candidates for a kidney transplant may need dialysis while waiting for a kidney to become available.
Support Groups
See: Kidney disease - support group
Outlook (Prognosis)
Many people are not diagnosed with chronic kidney disease until they have lost most of their kidney function.
There is no cure for chronic kidney disease. Untreated, it usually worsens to end-stage renal disease. Lifelong treatment may control the symptoms of chronic kidney disease.
Possible Complications
- Anemia
- Bleeding from the stomach or intestines
- Bone, joint, and muscle pain
- Changes in blood sugar
- Damage to nerves of the legs and arms (peripheral neuropathy)
- Dementia
- Fluid buildup around the lungs (pleural effusion)
- Heart and blood vessel complications
- Congestive heart failure
- Coronary artery disease
- High blood pressure
- Pericarditis
- Stroke
- High phosphorous levels
- High potassium levels
- Hyperparathyroidism
- Increased risk of infections
- Liver damage or failure
- Malnutrition
- Miscarriages and infertility
- Seizures
- Swelling (edema)
- Weakening of the bones and increased risk of fractures
Prevention
Treating the condition that is causing the problem may help prevent or delay chronic kidney disease. People who have diabetes should control their blood sugar and blood pressure levels and should not smoke.
References
Tonelli M, Pannu N, Manns B. Oral phosphate binders in patients with kidney failure. N Engl J Med. 2010;362:1312-1324.
Abboud H, Henrich WL. Clinical practice. Stage IV chronic kidney disease. N Engl J Med. 2010;362:56-65.
Upadhyay A, Earley A, Haynes SM, Uhlig K. Systematic review: blood pressure target in chronic kidney disease and proteinuria as an effect modifier. Ann Intern Med. 2011;154:541-548.
KDOQI. KDOQI Clinical Practice Guideline and Clinical Practice Recommendations for anemia in chronic kidney disease: 2007 update of hemoglobin target. Am J Kidney Dis. 2007; 50:471-530.
KDOQI; National Kidney Foundation II. Clinical practice guidelines and clinical practice recommendations for anemia in chronic kidney disease in adults. Am J Kidney Dis. 2006;47(5 Suppl 3):S16-S85.
Kidney Disease Outcomes Quality Initiative (K/DOQI). K/DOQI clinical practice guidelines on hypertension and antihypertensive agents in chronic kidney disease. Am J Kidney Dis. 2004; 43(5 Suppl 1):S1-S290.
Reviewed By: Herbert Y. Lin, MD, PhD, Nephrologist, Massachusetts General Hospital; Associate Professor of Medicine; Harvard Medical School. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
